The program described herein will train postdoctoral fellows for a career in academic oncology. Candidates with an MD or both an MD and PhD degrees who have completed training in internal medicine will be admitted to the three-year program. The first year of the program consists of an intensive experience in clinical oncology. During the remainder of the program, the trainees will devote the majority of their time to research-based study, either in the laboratory or in a clinical setting. Fellow stipend support for the research training is provided by this grant. More than three years of training is often required to complete a research project and to become competitive for an academic position. Trainees and their preceptors obtain support beyond this training grant for these additional years. For each fellow, research training will be supervised by a full-time faculty member in the Division of Oncology, or by one of a number of associate faculty members at Stanford University representing the basic science disciplines relevant to cancer, such as biological sciences, biochemistry, developmental biology, epidemiology, genetics and genomics, immunology, pathology, population sciences, hematopoietic stem cell transplantation, disease prevention, biostatistics and bioinformatics. At the conclusion of their training, individuals will be prepared for careers as independent investigators at the forefront of science and medical oncology.